1. Field of the Invention
This invention relates to a radiation-sensitive resin composition containing an alkali-soluble resin. More particularly, this invention relates to a radiation-sensitive resin composition suitable as a resist for use in the fabrication of integrated circuits, which is sensitive to a variety of radiations including ultraviolet radiation such as g-rays, i-rays, and the like; far-ultraviolet radiation such as KrF excimer laser radiation, and the like; X-radiation such as synchrotron radiation, and the like; and charged-particle radiation such as electron radiation, and the like; in particular, ultraviolet radiation and far-ultraviolet radiation.
2. Description of the Prior Art
Positive resists are widely used in the fabrication of integrated circuits, and as integrated circuits have become more highly integrated in recent years, there have been desired positive resists capable of forming a resist pattern more improved in resolution.
Generally in order to modify resist materials for improving the resolution of positive resists, there is known, for example, a method comprising lowering the molecular weight of an alkali soluble resin used in the resist. However, the method causes the problem that the resist lowers in heat resistance. While, as an improvement in resolution due to modification of processes, there is known a method comprising increasing the numeral aperture (NA) of a stepper. However, this method causes the problem that depth of focus (focal latitude) becomes narrow, so that simultaneously improvement of resist materials is required. One of countermeasures for the improvement of resist materials is, for example, to increase the amount of a quinonediazide compound added for improving focal latitude. However, an increase in the amount of the quinonediazede compound results in deteriorating developability.